Method for preparing high temperature NTC (Negative Temperature Coefficient) thermistor material

A technology of negative temperature coefficient and thermistor, which is applied in the field of preparation of high temperature negative temperature coefficient thermistor materials to achieve the effect of good linearity and stable high temperature performance

Inactive Publication Date: 2013-04-03
HUAZHONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Ni published by Yang Jianfeng et al. 0.6 mn 2.0-x A1 0.4 sn x o 4 High-temperature NTC materials are also spinel structures, and are only suitable for 300-500°C

Method used

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  • Method for preparing high temperature NTC (Negative Temperature Coefficient) thermistor material
  • Method for preparing high temperature NTC (Negative Temperature Coefficient) thermistor material
  • Method for preparing high temperature NTC (Negative Temperature Coefficient) thermistor material

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preparation example Construction

[0022] Such as figure 1 As shown, the preparation method of the high temperature negative temperature coefficient thermistor material of the present invention comprises the following steps:

[0023] (1) According to CaWO 4 -xCeTi y o 2y+2 The formulation weighs analytically pure powdered CaCO 3 , CeO 2 、TiO 2 、WO 3， Put the powder into a ball mill tank, add deionized water according to the mass ratio of powder to deionized water at 1:2, add ball millstone at a mass ratio of powder to ball millstone at 1:3, and mill for four hours; where x takes The value range is 0.2 to 0.5, and the value range of y is 1 to 3. Specifically, according to CaWO 4 -xCeTi y o 2y+2 The formula can determine the molar ratio of the four elements Ca, Ce, Ti, and W as 1:x:xy:1, so that the powder CaCO can be further determined according to these four elements 3 , CeO 2 、TiO 2 、WO 3 The molar ratio between;

[0024] (2) Dry the ball-milled mixture in an oven to obtain a dry powder, which is...

Embodiment 1

[0030] (1) According to CaWO 4 -0.2CeTi 1 o 4 The formulation weighs analytically pure powdered CaCO 3 , CeO 2 、TiO 2 、WO 3， Put the powder into a ball mill tank, add deionized water according to the mass ratio of powder to deionized water 1:2, add ball millstone according to the mass ratio of powder to ball millstone 1:3, and mill for four hours;

[0031] (2) Dry the ball-milled mixture in an oven to obtain a dry powder, which is ground and passed through an 80-mesh sieve;

[0032] (3) Pre-burn the fine powder obtained in step (2) at 900-1100°C for 2-5h;

[0033] (4) Ball mill and dry the pre-burned powder again;

[0034] (5) After grinding the dried powder, pass it through a 80-mesh sieve, add PVA with a mass ratio of 6%-10% and a concentration of 5-10mol% in the powder as a binder for uniform mixing, and The obtained granulated powder is pressed into a sheet sample by a dry pressing method;

[0035] (6) Put the dry-pressed sample into a high-temperature furnace for...

Embodiment 2

[0037] (1) According to CaWO 4 -0.2CeTi 2 o 6 The formulation weighs analytically pure powdered CaCO 3 , CeO 2 、TiO 2 、WO 3， Put the powder into a ball mill tank, add deionized water according to the mass ratio of powder to deionized water 1:2, add ball millstone according to the mass ratio of powder to ball millstone 1:3, and mill for four hours;

[0038] (2) Dry the ball-milled mixture in an oven to obtain a dry powder, which is ground and passed through an 80-mesh sieve;

[0039] (3) Pre-burn the fine powder obtained in step (2) at 900-1100°C for 2-5 hours;

[0040] (4) Ball mill and dry the pre-burned powder again;

[0041] (5) After grinding the dried powder, pass it through a 80-mesh sieve, add PVA with a mass ratio of 6%-10% and a concentration of 5-10mol% in the powder as a binder for uniform mixing, and The obtained granulated powder is pressed into a sheet sample by a dry pressing method;

[0042] (6) Put the dry-pressed sample into a high-temperature furnace ...

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Abstract

The invention discloses a method for preparing a high temperature NTC (Negative Temperature Coefficient) thermistor material, which comprises the following steps of: according to a formula of CaWO4-xCeTiyO2y+2, weighing and analyzing pure powdered CaCO3, CeO2, TiO2 and WO3, placing the powder into a ball milling tank, adding deionized water and zirconium ball grinding stone and carrying out ball milling for four hours; drying ball-milled slurry, grinding the dried powder and sieving the powder through a 80-mesh sieve; presintering the sieved powder, ball-grinding the presintered powder again, drying and grinding the powder and sieving the power through the 80-mesh sieve to obtain uniform and fine powder; and finally, placing a dry-pressed sample into a high temperature furnace to sinter so as to obtain the thermistor material. A main crystal phase of the thermistor material prepared by the method disclosed by the invention is a scheelite phase; the thermistor material has room temperature resistivity of 5.642*10<6> to 1.982*10<9> ohm.cm and has material constant of 5,077 to 7,275K; in the integral test temperature range, a resistor temperature relation curve LnRho-1000 / T has good linearity; and the method is suitable for temperature measurement in the wide temperature range of room temperature to 1,000 DEG C.

Description

technical field [0001] The invention belongs to the technical field of thermosensitive materials, and more specifically relates to a preparation method of a high-temperature negative temperature coefficient thermistor material. Background technique [0002] In recent years, with the widespread use of automotive exhaust catalytic converters, high-temperature NTC thermistors have become more and more important. They are used to prepare temperature sensors for automobile exhaust temperature measurement and optimal temperature monitors for exhaust catalytic converters. In the environment of automobile exhaust, the working temperature of the sensor varies from room temperature to 1000°C. The temperature sensors suitable for measuring in this temperature range include thermocouples and NTC thermistor temperature sensors. High-temperature NTC thermistor temperature sensor has the advantages of large output signal and no need for complicated signal amplification and processing circ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/495C04B35/462C04B35/50C04B35/622
Inventor 郝永德徐华易纪婉雪
Owner HUAZHONG UNIV OF SCI & TECH
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